A powerful war party of the Black Dragonflight, led by the fearsome Twilight dragon, Halion, have launched an assault upon the Ruby Sanctum beneath Wyrmrest Temple. By destroying the sanctum, the Black Dragonflight look to crush those that would stand in the way of their master's reemergence into Azeroth and to ultimately shatter the Wyrmrest Accord – the sacred bond that unites the dragonflights.

The battle that is to come will surely deal a crippling blow to the Red Dragonflight, however, it is up to you to stop this unprecedented offensive and defend the Ruby Sanctum. First you must face the assault of Halion's servants, Saviana Ragefire, Baltharus the Warborn, and General Zarithrian, before squaring off against Halion the Twilight Destroyer, a new and deadly force in this realm.

The Ruby Sanctum will feature 10- and 25-player content, Heroic difficulties and all-new rewards! Stay tuned for more information as we get closer to its release.

From the text, it sounds like we're getting four bosses in the Ruby Sanctum, unless they've taken a Northrend Beasts gauntlet-style approach to the encounters, or perhaps even another council-style battle. Later in the thread, Zarhym suggest that this may only be the beginning of Deathwing's attempts at shattering the Accord, so we may see the other Sanctums open before Cataclysm's launch.